Image communication apparatus for controlling a mechanical motion of a communication partner

ABSTRACT

An image communication apparatus generates a command, which controls a communication partner to cause a part of the communication partner to move mechanically, to be transmitted through a communication line. The apparatus further prevents the communication partner from operating incorrectly according to the command which is transmitted after a predetermined delay time of the communication line.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image communication system,apparatus, and method for transmitting and receiving an image to andfrom remote sites over a digital communication line such as IntegratedService Digital Network (ISDN).

2. Related Background Art

With recent development of image compression and coding techniques aswell as recent prevalence of high speed, high quality digitalcommunication lines typically ISDN, various image communication systemshave been developed which conform with Recommendations stipulated foraudio video (AV) services such as television (TV) conference systems.

A TV conference system, a typical image communication system, isoperated generally by preparing a TV conference room to have aconference with partners at a remote TV conference room. This conferenceis usually had by a plurality of participants in TV conference rooms ina multi-to-multi person style.

There are several methods of taking an image of a participant orparticipants in a TV conference room for the transmission of the imagefrom its own TV conference terminal to a partner TV conference terminal.With one method, zooming of an image photographing unit (e.g., videocamera) is set to a wide angle side to take the images of allparticipants, or with another method, a photographing unit with atilting mechanism is used to take the image of a particular participant.

As one example of using the tilting mechanism of the photographing unit,a method has been proposed whereby a microphone is installed for each ofall TV conference participants, the sound levels are checked, and thephotographing unit is automatically moved toward the participant withthe largest sound level. In most of TV conference systems, however, thetilting control of the photographing unit is performed by an operatorwho manipulates an operation console of the TV conference system.

Some image photographing units used by such a TV conference system canperform zooming control, focussing control as well as tilting control inthe vertical and horizontal directions, in response to controlinformation (command) supplied from the operation console. Further, someimage photographing units have an automatic focussing function ofautomatically measuring a distance to an object and adjusting the focusof the object. Still further, some image photographing units have aplurality of range finding points on a photographing screen to adjustthe focus of an arbitrary or particular object on the photographingscreen.

In some TV conference systems and image photographing units having thesame command system, the image photographing unit not only at the ownside station but also at the partner side station can be controlled. Insuch TV conference systems, control information for the imagephotographing unit is transmitted to a TV conference terminal at thepartner side station to control the image photographing unit at thepartner side station.

In a TV conference system in which the image photographing unit iscontrolled by an operator who manipulates an operation console, forexample, the direction of the image photographing unit is controlled bydepressing tilt control keys (right, left, up, and down keys) of theimage photographing unit. However, with this method, because thecorrespondence between the tilt direction of the image photographingunit and the tilt control key differs depending on the type of each TVconference system, the operator becomes confused in changing thephotographing direction of the photographing unit at the own sidestation.

For example, consider the case where there are a window 100 (hereinaftercalled self-portrait display window) for displaying an image on theimage display unit at the own side station and a window 101 (hereinaftercalled partner portrait display window) for displaying an image at apartner side station on the image display unit at the own side station.In this case, in order to move an object 103 displayed at the left ofthe partner portrait display window 101 to the center of the window 101,the photographing direction of the image photographing unit 105 at thepartner side station (hereinafter called partner portrait photographingunit) is required to change to the direction indicated by an arrow 107.In this case, an operator usually depresses a “left key” of the tiltcontrol keys.

On the other hand, in order to move an object 102 displayed at the leftof the self-portrait display window 100 to the center of the window 100,the photographing direction of the image photographing unit 104 at theown side station (hereinafter called self-portrait photographing unit)is required to change to the direction indicated by an arrow 106.

Two types of manipulation by an operator of the tilt control keys may behad:

a) Depressing “left key”, being coincident with the tilt direction asviewed from the self-portrait photographing unit 104, and

b) Depressing “right key”, being coincident with the tilt direction asviews from the object 102.

In some TV conference systems, an operator can select either one of thetwo types, by setting the system to this effect.

As above, in a conventional TV conference system, because thecorrespondence between the tilt direction of the self-portraitphotographing unit 104 and the tilt control key is different, theoperator becomes confused in changing the photographing direction of thephotographing unit.

Apart from the above, in controlling the partner portrait photographingunit 105 from the own side station, each time a key of the operationconsole at the TV conference terminal at the own side station isdepressed, for example, each time the “left key” is depressed, a commandsuch as “change the photographing direction of the partner portraitphotographing unit 105) is transmitted over a communication line to theTV conference terminal at the partner side station. In response to thiscommand, the photographing direction of the partner portraitphotographing unit 105 is changed by an amount preset for this command.During or after this change, an image at the partner side station istransmitted over the communication line to the image display unit at theown side station, and displayed on the partner portrait display window101.

After an operator depresses the control key for controlling the partnerportrait photographing unit 105 at the TV conference terminal at the ownside station, a new image reflecting this control is displayed on thepartner portrait display window 101 at the own side station. During thisperiod, there is a delay time in transferring a control command or imagedata and in coding and decoding an image. Therefore, an operator tendsto depress the control key at the TV conference terminal at the own sidestation, more often than necessary, making difficult to change thedirection of the partner portrait photographing unit 105 by a desiredamount.

Such a problem occurs also in performing a zooming control of thepartner portrait photographing unit 105 from the own side station.Specifically, after an operator depresses the zooming control key at theown side station, an image at the partner side station reflecting thecontrol change is displayed on the partner portrait display window 101.During this period, there is a delay time so that it is difficult tozoom the image to a desired size.

Still further, if there are a plurality of participants in one TVconference room and a distance from the image photographing unit to eachparticipant is different, it is necessary for a conventional TVconference system to manually adjust the focus, resulting in acomplicated focus adjustment operation. Although an image photographingunit with an automatic focussing function is known, this unitautomatically focusses to a participant located at the center of thedisplay screen. Therefore, the participants other than the participantat the center of the display screen are out of focus and it is difficultto clearly discriminate between those participants.

Such a delay time is associated not only with the above-describedcontrols but also, for example, with the case where an operator draws adesired image with a pointing device.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an imagecommunication system, apparatus, and method capable of independently orcollectively solving the above-described problems.

It is another object of the present invention to solve the problemsassociated with a response delay generated if a command is transmittedvia a communication line.

In order to achieve the above objects, a preferred embodiment of theinvention discloses an image communication apparatus comprising: meansfor generating a command, which controls a communication partner, to betransmitted through a communication line; and means for preventing thecommunication partner from operating incorrectly according to thecommand which is transmitted after a predetermined delay time of thecommunication line.

It is still another object of the invention to provide an imagecommunication system and method capable of reliably controlling devicesat a communication partner from the image transmission side.

It is another object of the present invention to provide an imagecommunication apparatus for such a system achieving the above object.

It is a further object of the present invention to provide an imagecommunication system easy to be used by an operator.

It is a still further object of the present invention to provide animage communication system achieving the above objects, capable offacilitating the control of devices at a communication partner by anoperator.

It is another object of the present invention to provide a novel imagecommunication system and apparatus.

The other objects and advantages of the present invention will becomeapparent from the following detailed description of the embodiments whenread in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing the main circuit portions of theinvention.

FIG. 2 is a block diagram showing the structure of a TV conferencesystem according to an embodiment of the invention.

FIGS. 3A and 3B are diagrams illustrating the operation of the controlof a photographing direction of the TV conference system according tothe embodiment.

FIG. 4 is a diagram illustrating an example of a method of calculatingcontrol information of a photographing direction in the TV conferencesystem according to the embodiment.

FIG. 5 is a flow chart illustrating the process of controlling thephotographing direction of the self-portrait or partner portraitphotographing unit when a position is designated on the self-portrait orpartner portrait display window of the TV conference system of thisembodiment.

FIGS. 6A and 6B are diagrams illustrating the operation of controllingthe photographing area in the TV conference system according to theembodiment.

FIGS. 7A and 7B are diagrams illustrating the operation of controllingthe focal position in the TV conference system according to theembodiment.

FIG. 8 is a diagram illustrating a control selection operation for theimage photographing unit in the TV conference system according to theembodiment.

FIG. 9 is a diagram showing an example of a display on the image displayunit on which selectable focal positions are displayed for the controlof a focal position in the TV conference system according to theembodiment.

FIG. 10 is a diagram illustrating the control operation for thephotographing direction of the image photographing unit in aconventional TV conference system.

FIG. 11 is a block diagram showing the main circuit portions of thesecond embodiment of the invention.

FIG. 12 is a sequence chart illustrating a process flow when thephotographing control inhibition unit is controlled by the control timepredicting unit and time measuring unit in the TV conference system ofthis embodiment.

FIG. 13 is a sequence chart illustrating a process flow when thephotographing control inhibition unit is controlled by the controlcompletion informing unit in the TV conference system of thisembodiment.

FIG. 14 is a flow chart illustrating a process flow when controlinformation is inputted from the photographing control unit while thephotographing control inhibition unit is controlled by the control timepredicting unit and time measuring unit in the TV conference system ofthis embodiment.

FIG. 15 is a flow chart illustrating a process flow when controlinformation is inputted from the photographing control unit while thephotographing control inhibition unit is controlled by the controlcompletion informing unit in the TV conference system of thisembodiment.

FIG. 16 is a flow chart illustrating an operation when controlinformation is inputted from the photographing control unit while thephotographing control inhibition unit is controlled by the controlcompletion informing unit in the TV conference system of thisembodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a block diagram showing the main circuit portions of theinvention.

Referring to FIG. 1, an image communication system at the own sidestation is constituted by an image communication apparatus having aself-portrait photographing unit 67 and an image display unit 68 andother units 51 to 66. The image communication system includes othervarious units shown in FIG. 2 which are not depicted in FIG. 1.

An image communication system at the partner side station is constructedin the similar manner to the system at the own side station, only apartner side station image photographing unit 69 for taking an image onthe partner side station being shown in FIG. 1. Image data and a plentyof control information are transmitted and received between own side andpartner side stations to perform, for example, a TV conference.

Referring to FIG. 1, a position designating unit 51 designates anarbitrary point on an image displayed on the image display unit 68. Anarea designating unit 52 designates an arbitrary area on an imagedisplayed on the image display unit 68. These position and areadesignating units 51 and 52 are used for changing the photographingstate (photographing direction, photographing area, photographingposition, and so on) of the photographing units 67 and 69 at the ownside and partner side stations.

A control determining unit 53 determines a designation of a point orarea by the position or area designating unit 51 or 52, and alsodetermines a selection of a particular control, if any, by a controlselecting unit 54. The control selecting unit 54 selects one of controlsrespectively made by a photographing direction control unit 56, aphotographing area control unit 59, and a focal position control unit64.

An image photographing unit discriminating unit 55 discriminates betweenthe image photographing units, the discriminated image photographingunit having the image display unit on which an image having a point orarea designated by the position or area designating unit 51 or 52 isdisplayed.

For example, consider both a self-portrait display window 68 a fordisplaying an image at the own side station on the image display unit 68and a partner portrait display window 68 b for displaying an image atthe partner side station on the image display unit 68 are displayed. Inthis case, the image photographing unit discriminating unit 55discriminates between the self-portrait photographing unit 67 taking theimage on the self-portrait display window 68 a and the partner portraitphotographing unit 69 taking the image on the partner portrait displaywindow 68 b. That is, the image photographing unit discriminating unit55 discriminates between the self-portrait display window 68 a andpartner portrait display window 68 b, the discriminated one having adesignated point or area. If there is a plurality of image display unitsat the own side or partner station, the unit 55 also discriminates animage display unit on which display unit a point or area on an image hasbeen designated, from other display units.

In accordance with the determination result of the control determiningunit 53 and the discrimination result of the image photographing unitdiscriminating unit 55, one of the photographing direction control unit56, photographing area control unit 59, focal position control unit 64performs its control and calculates control information for the controlof the corresponding image photographing unit.

In accordance with the determination result of the control determiningunit 53 and the discrimination result of the image photographing unitdiscriminating unit 55, the photographing direction control unit 56calculates control information for changing the photographing directionof the self-portrait photographing unit 67 or partner portraitphotographing unit 69 right, left, up, or down. For example, incalculating control information for the self-portrait photographing unit67, first, a photographing state inspecting unit 57 inspects the currentphotographing state of the self-portrait photographing unit 67.

In accordance with the information of the photographing state of theself-portrait photographing unit 67 obtained through the inspection bythe photographing state inspecting unit 57, a photographing directioncontrol information calculation unit 58 calculates control informationfor changing the photographing direction of the self-portraitphotographing unit 67 so as to move a point designated by the positiondesignating unit 51 to the center of the self-portrait display window 68a. The details of calculating this control information will be latergiven.

In calculating control information for the partner portraitphotographing unit 69, the photographing state inspecting unit 57inspects the current photographing state of the partner portraitphotographing unit 69 instead of the self-portrait photographing unit67. The other operations are similar to the above.

In accordance with the determination result of the control determiningunit 53 and the discrimination result of the image photographing unitdiscriminating unit 55, the photographing area control unit 59calculates control information (control information for zooming) forcontrolling the self-portrait photographing unit 67 or partner portraitphotographing unit 69. For example, in calculating control informationfor the self-portrait photographing unit 67, first a rectangle areagenerating unit 60 generates a rectangle area including an areadesignated by the area designating unit 52.

Then, assuming that the center of the rectangle area is the pointdesignated by the position designating unit 51, a photographing stateinspecting unit 61 and a photographing direction control informationcalculating unit 62 calculate control information for changing thephotographing direction of the self-portrait photographing unit 67 so asto move the center of the rectangle area to the center of theself-portrait display window 68 a, similar to the operations made by thephotographing state inspecting unit 57 and the photographing directioncontrol information calculating unit 58. A focal length calculating unit63 calculates control information for changing the focal length so as tomake the size of the rectangle area equal to the size of theself-portrait display window 68 a.

In accordance with the determination result of the control determiningunit 53 and the discrimination result of the image photographing unitdiscriminating unit 55, the focal position control unit 64 calculatescontrol information for controlling the focal position of theself-portrait photographing unit 67 or partner portrait photographingunit 69. For example, in calculating control information for theself-portrait photographing unit 67, a focal position controlinformation calculating unit 65 calculates control information forsetting the focal position of the self-portrait photographing unit 67 tothe point designated by the position designating unit 51.

The control information calculated by the photographing directioncontrol unit 56, photographing area control unit 59, and focal positioncontrol unit 64 in the above manner is supplied to a control informationinforming unit 66. In accordance with the discrimination result of theimage photographing unit discriminating unit 55, the control informationinforming unit 66 informs the self-portrait photographing unit 67 orpartner portrait photographing unit 69 of the control information. Thecontrol information is transmitted via a communication line to the imagephotographing unit 69 of the image communication system at the partnerside station.

In accordance with the notified control information, the self-portraitphotographing unit 67 and the partner portrait photographing unit 69execute a process for changing a photographing state (photographingdirection, photographing area, focal position, and so on). The imagephotographing units 67 and 69 include an unrepresented controller whichreceives the control information and executes the change process for thephotographing state.

An image taken by the self-portrait photographing unit 67 is displayedon the self-portrait display window 68 a, and on an unrepresented imagedisplay unit at the partner side station via the communication line. Animage taken by the partner portrait photographing unit 69 is displayedon the unrepresented display unit at the partner side station, and onthe partner portrait display window 68 b at the own side station via thecommunication line.

As above, only by designating a point or area on an image displayed onthe self-portrait display window 68 a or the partner portrait displaywindow 68 b, the photographing state (photographing direction,photographing area, focal position, and so on) of the imagephotographing unit 67 or 69 taking the image can be controlled reliably,while presenting easy operation of each control.

In controlling the photographing state of the partner portraitphotographing unit 69 from the own side station, a delay time from adesignation of a point or area to a display of a designation reflectednew image on the partner portrait display window 68 b poses no practicalproblem. Specifically, if an operator designates a position or area onthe partner portrait display window 68 b at the own side stationrelative to which the photographing direction, photographing area, focalposition, and so on are changed, the photographing state of the partnerportrait photographing unit 69 can be automatically changed inaccordance with the designated point or area information. Therefore,each control of the photographing direction, photographing area, orfocal position can be made easily while satisfying the intention of theoperator.

FIG. 2 is a block diagram showing the structure of a TV conferencesystem according to an embodiment of the invention.

Referring to FIG. 2, reference numeral 1 represents a handset which isone of audio input/output devices, reference numeral 2 represents amicrophone which is one of the audio input/output devices, and referencenumeral 3 represents a speaker which is one of the audio input/outputdevices. Reference numeral 4 represents an audio interface unit whichperforms a switching process between the handset 1, microphone 2, andspeaker 3 and a detecting process of an on/off-hook state of the handset1, under the control of a system controller 14.

Reference numeral 5 represents an audio coding/decoding unit whichexecutes a coding process of an audio transmission signal and a decodingprocess of an audio reception signal under the control of the systemcontroller 14, in accordance with audio signal coding/decodingalgorithms such as 64 kbps PCM A-law, 64 kbps PCM μ-law, 64 kbps/56kbps/48 kbps SB-ADPCM, 32 kbps ADPCM, 16 kbps (e.g., APC-AB), and 8kbps.

Reference numeral 6 represents a camera which is one of imagephotographing units. Control information is supplied to this camera 6 toenable the control of photographing direction, zooming, focal positionadjustment, and the like. Reference numeral 7 represents a writing/imagecamera which is one of the image photographing units and is used fortaking an image of a resource such as a document to be used forconference.

Reference numeral 8 represents a display which is one of image displayunits and is used for displaying an image from the camera 6 orwriting/image camera 6 or an image received from the TV conferencesystem at the partner side station via the communication line, on theself-portrait display window or the partner portrait display window.

Reference numeral 9 represents a video interface unit which executesvarious processes, such as a switching process between display screens,a synthesizing process of image signals, and a photographing directioncontrolling process of controlling the photographing direction of theimage photographing unit, under the control of the system controller 14.Reference numeral 10 represents a video coding/decoding unit whichexecutes a coding process of a video transmission signal and a decodingprocess of a video reception signal in accordance with ITU-TRecommendations H.261.

Reference numeral 11 represents a data terminal. Reference numeral 12represents a data interface unit which transfers transmission data fromthe data terminal 11 or system controller 14 to a multiple separatingunit 15, or reception data from the partner side station to the dataterminal 11 or system controller 14. Reference numeral 13 represents anoperating unit which is used for inputting control information for thevarious controls of this system. The operating unit 13 has, for example,a keyboard, a coordinate input device (such as mouse and tablet), andother devices.

The system controller 14 has a CPU, a ROM, a RAM, and other storagedevices and supervises and controls the whole system. In accordance withITU-T Recommendations H.221, the multiple separating unit 15 converts anaudio signal from the audio coding/decoding unit 5, a video signal fromthe video coding/decoding unit 10, and a data signal from the datainterface unit 12, into a BAS (bit rate assignment signal), and executesa multiplex process in the unit of transmission frame. It also executesa separation process in the unit of reception frame by separatingsignals into audio, video, and data signals and supplying theseseparated signals to the audio coding/decoding unit 5, videocoding/decoding unit 10, and data interface unit 12.

Reference numeral 16 represents a line interface unit which is connectedto the communication line such as ISDN and controls the line under thecontrol of the system controller 14 in accordance with an ISDN user-netinterface.

Local and remote TV conference systems having the structure describedabove are interconnected together by an ISDN communication line totransfer audio, video, and control information to conduct a TVconference.

The video interface unit 9 and system control unit 14 constitute thecontrol determining unit 53, image photographing unit discriminatingunit 55, photographing direction control unit 56, photographing areacontrol unit 59, focal position control unit 64, and control informationinforming unit 66.

FIGS. 3A and 3B are diagrams illustrating the operation of the controlof a photographing direction of the camera 6 of the TV conference systemof this embodiment.

Referring to FIGS. 3A and 3B, reference numeral 300 represents an imagedisplay window which is one of the image display devices, referencenumeral 301 represents an object photographed by the camera 6, andreference numeral 302 represents a pointing cursor for pointing anarbitrary point on the image displayed on the image display window 300.

Consider now changing the photographing direction of the camera 6 so asto move an object 301 at the position shifted from the center of theimage display window 300 as shown in FIG. 3A to the center of the imagedisplay window 300 as shown in FIG. 3B. In the TV conference system ofthis embodiment, the photographing direction of the camera 6 can beautomatically changed by designating the face of the object 301 to bemoved to the center of the image display window 300, with the pointingcursor 302 or upon an instruction by the cursor 302, e.g., a click ifthe cursor 302 is constituted by a mouse.

FIG. 4 is a diagram illustrating an example of a method of calculatingcontrol information of a photographing direction of the camera 6 in theTV conference system of this embodiment.

Referring to FIG. 4, reference numeral 400 represents an image displaywindow, reference numeral 401 represents an object photographed by thecamera 6, reference numeral 402 represents a point on the image displaywindow 400 designated with the pointing cursor 302, reference numeral403 represents a lens of the camera 6, and reference numeral 404represents a focussed image taken by the camera 6.

In this embodiment, in accordance with the designated point 402 on theimage display window 400 and the state of the camera 6, thephotographing direction control information of the camera 6 iscalculated so as to move the object 401 designated by the point 402 tothe center of the image display window 400. An example of thecalculation method will be described below.

First, for the photographing direction control information of the camera6 in the horizontal direction, a tilt angle θ_(x) in the horizontaldirection of the photographing direction of the camera 6 shown in FIG. 4is calculated.

The tilt angle θ_(x) in the horizontal direction of the photographingdirection of the camera 6 can be given by the following equation (1):

tan θ_(x) =MX/mf

θ_(x)=tan⁻¹ (MX/mf)  (1)

where f is a focal length from the lens 403 to the focussed image 404, Mis a horizontal width of the image display window 400, X is a horizontaldistance from the center of the image display window 400 to thedesignated point 402, m is a horizontal width of the focussed image, andx is a horizontal distance from the center of the focussed image 404 tothe point corresponding to the designated point 402.

In the similar manner, for the photographing direction controlinformation of the camera 6 in the vertical direction, a tilt angleθ_(y) in the vertical direction of the photographing direction of thecamera 6 shown in FIG. 4 is calculated.

The tilt angle θ_(y) in the vertical direction of the photographingdirection of the camera 6 can be given by the following equation (2):

tan θ_(y) =NY/nf

θ_(y)=tan⁻¹ (NY/nf)  (2)

where N is a vertical width of the image display window 400, Y is avertical distance from the center of the image display window 400 to thedesignated point 402, n is a vertical width of the focussed image, and yis a vertical distance from the center of the focussed image 404 to thepoint corresponding to the designated point 402.

FIG. 5 is a.flow chart illustrating the process of controlling thephotographing direction of the self-portrait or partner portraitphotographing unit when a position is designated on the self-portrait orpartner portrait display window of the TV conference system of thisembodiment. The process illustrated in this flow chart will be describedwith reference to the block diagram shown in FIG. 1.

Referring to FIG. 1, first at Step S500 the control determining unit 53determines whether the position designating unit 51 has designated thephotographing direction of either the self-portrait display window 68 aor partner portrait display window 68 b. If designated, the flowadvances to Step S501, and if not, the flow repeats the process at StepS500.

At Step S501 the image photographing unit discriminating unit 55discriminates between the own side station and the partner side station,at the discriminated one the image photographing unit taking the imagedisplayed on the designated window. If the image displayed on thedesignated window is taken at the own side station, the flow advances toStep S502, and if not, the flow advances to Step S505.

At Step S502 the photographing state inspecting unit 57 inspects thecurrent state of the self-portrait photographing unit 67, the currentstate including, for example, the focal length f from the lens 403 tothe center of the focussed image 404, the vertical and horizontal widthsfrom the center of the image display window 400 to the designated point402, and other parameters shown in FIG. 4. Next, at Step S503 thephotographing direction control information calculating unit 58calculates control information for changing the photographing directionof the self-portrait photographing unit 67 in the manner described withFIG. 4, in accordance with the position of the point on theself-portrait display window 68 a designated at Step S500 and the stateof the self-portrait photographing unit 67 inspected at Step S502.

At Step S504 the control information informing unit 66 informs theself-portrait photographing unit 67 of the photographing directioncontrol information of the self-portrait photographing unit 67calculated at Step S503. In accordance with the photographing directioncontrol information, the photographing direction is changed in thevertical direction so as to move the object to the center of theself-portrait display window 68 a.

On the other hand, at Step S505 following Step S501, the photographingstate inspecting unit 57 inspects the current state of the partnerportrait photographing unit 69. The current state of the partnerportrait photographing unit 69 can be given by requesting it from the TVconference terminal at the partner side station via the communicationline.

Next, at Step S506 the photographing direction control informationcalculating unit 58 calculates control information for changing thephotographing direction of the partner portrait photographing unit 69 inthe manner described with FIG. 4, in accordance with the position of thepoint on the partner portrait display window 68 b designated at StepS500 and the state of the partner portrait photographing unit 69inspected at Step S505.

At Step S507 the control information informing unit 66 transmits thephotographing direction control information of the partner portraitphotographing unit 69 calculated at Step S506 to the TV conferenceterminal at the partner side station over the communication line. Thepartner portrait photographing unit 69 changes the photographingdirection in the vertical and horizontal directions in accordance withthe photographing direction control information received from the TVconference terminal at the own side station.

An image at the partner side station while changing the photographingdirection or after the photographing direction change, is supplied viathe communication line to the image display unit 68 at the own sidestation and displayed on the partner portrait display window 68 b.

FIGS. 6A and 6B are diagrams illustrating the operation of controllingthe photographing area of the camera 6 in the TV conference system ofthe embodiment.

Referring to FIGS. 6A and 6B, reference numeral 600 represents an objectphotographed by the camera 6, reference numeral 601 represents an areaon the image display window 300 designated with the pointing cursor 302,reference numeral 602 represents a rectangle area including thedesignated area 601, the rectangle area having the same aspect ratio asthe photographing area of the camera 6, and reference numeral 603represents the center of the rectangle area 602.

In the TV conference system of this embodiment, when the area 601 isdesignated with the pointing cursor 302 as shown in FIG. 6A, therectangle area 602 including the area 601 is generated. Similar to thephotographing direction control procedure described with reference toFIGS. 3A and 3B and FIG. 4, the photographing direction of the camera 6is changed to the direction toward the center 603 of the rectangle area602. Similar to the calculation method described with reference to FIG.4, the focal length f is calculated in order to focus the image 404 onthe rectangle area 602 to thereby automatically perform a zoomingprocess for the designated area 601 as shown in FIG. 6B.

FIGS. 7A and 7B are diagrams illustrating the operation of controllingthe focal position of the camera 6 in the TV conference system of theinvention.

Referring to FIGS. 7A and 7B, reference numeral 700 represents an objectat the near position from the camera 6, and reference numeral 701represents an object at a far position from the camera 6.

In the TV conference system of this embodiment, the focal length is setto the object 700 at the center of the photographing area at the initialstage as shown in FIG. 7A, similar to a conventional TV conferencesystem.

In the TV conference system of this embodiment, as shown in FIG. 7A, asthe object 701 at the position shifted from the center of thephotographing area of the camera 6 is designated with the pointingcursor 302, the range finding of the designated point is carried out,and in accordance with the range finding result, the focus of the object701 is automatically set as shown in FIG. 7B. This range finding of thedesignated point can be performed by a known method commonly used byvideo cameras.

FIG. 8 is a diagram illustrating a control selection operation for thecamera 6 for selecting a particular control when a plurality of controlcommand are given to the camera 6 by designating an arbitrary positionor area on the image display unit in the TV conference system of thisembodiment.

FIG. 8 shows an example of an image displayed on the image display unit.Referring to FIG. 8, reference numeral 800 represents a controlselection window for the camera 6, reference numeral 801 represents aphotographing direction control selection button for the camera 6,reference numeral 802 represents a photographing area control selectionbutton for the camera 6, and reference numeral represents a focalposition control selection button for the camera 6.

Referring to FIG. 8, one of the three control selection buttons 801 to803 on the control selection window 800 is depressed by using thepointing cursor 302, and then an arbitrary position or area on the imagedisplay window 300 is designated to activate the control sequencecorresponding to the depressed button.

Specifically, when the photographing direction control selection button801 is depressed, the control sequence for the photographing directiondescribed with reference to FIGS. 3A and 3B is activated, and when thephotographing area control selection button 802 is depressed, thecontrol sequence for the photographing area described with reference toFIGS. 6A and 6B is activated. When the focal position control selectionbutton 803 is depressed, the control sequence for the focal positiondescribed with reference to FIGS. 7A and 7B is activated.

In this embodiment, when a position or area is designated on the imagedisplay unit like the display 8, control information for changing thephotographing direction or area of the image photographing unit like thecamera 6 is calculated for the designated position or area. Instead, theimage display unit may be divided into small blocks. In this case, thecontrol information of the image photographing unit for each dividedblock is stored in a table and the calculation of the controlinformation is replaced by a reference operation to the controlinformation table.

Still further, in the above embodiment, a focal position is adjustedrelative an arbitrary point designated on the image display unit.Instead, as shown in FIG. 9, a plurality of selectable range findingpoints 900 may be displayed on the image display unit. In this case,when one of the plurality of range finding points is designated, thefocal position control is performed for the designated range findingpoint 900.

As described above, the TV conference system of this embodiment includesdesignating means for designating an arbitrary point or area on an imagedisplayed on an image display unit, control information generating meansfor generating control information for changing the photographing stateof an image photographing unit in accordance with the information of thepoint or area designated by the designating means, and controlinformation informing means for informing the image photographing unitof the control information generated by the control informationgenerating unit. Accordingly, only by designating a desired point orarea on an image, the photographing state of the image photographingunit can be controlled, facilitating the manipulation required for thecontrol of the photographing state.

Further, the TV conference system further includes position designatingmeans for designating an arbitrary point on an image displayed on theimage display unit, photographing state inspecting means for inspectingthe state of the image photographing unit taking the image displayed onthe image display unit, photographing direction control informationgenerating means for generating control information for changing aphotographing direction of the image photographing unit in accordancewith the inspection result of the photographing state inspecting means,so as to move the position of a point to the center of the screen of theimage display unit, and control information informing means forinforming the image photographing unit of the control informationgenerated by the photographing direction control information generatingmeans. Accordingly, only by designating a desired point on a displayedimage, the photographing direction of the image photographing unit canbe changed in the direction intended by an operator, facilitating acontrol operation for changing the photographing direction of the imagephotographing unit toward a desired object displayed on the imagedisplay unit.

Still further, the TV conference system further includes areadesignating means for designating an arbitrary area on an imagedisplayed on the image display unit, and photographing area controlinformation generating means for generating control information for thephotographing area of the image photographing unit so as to match thearea designated by the area designating means. Accordingly, only bydesignating a desired area on an image, the photographing area of theimage photographing unit can be changed in conformity with the intentionof an operator, facilitating control operations for the photographingdirection and zooming of the image photographing unit so as to form asuitable image of an object displayed on the image display unit.

Further, the TV conference system further includes focal positioncontrol information generating means for generating control informationfor setting a focal position of the image photographing unit to a pointdesignated by the position designating means. Accordingly, only bydesignating a desired point on an image, the focal position of the imagephotographing unit can be changed matching the intention of an operator,facilitating a control operation of focusing a desired object displayedon the image display unit.

Still further, in the TV conference system, a plurality of imagephotographing unit blocks may be provided and the image display unit maybe divided into a plurality of display unit blocks, wherein imagephotographing unit discriminating means is provided for discriminatingan image photographing unit from the plurality of image photographingunits, which unit corresponds to the display unit on which the imagewith the designated point or area is displayed, and the imagephotographing unit discriminating means informs the image photographingunit discriminated by the image photographing unit discriminating meansof control information. Accordingly, a proper control of the imagephotographing unit is possible.even if an operator does not considerwhich image photographing unit among the plurality of imagephotographing units is to be controlled.

Furthermore, if there are a plurality of selectable controls for theimage photographing unit in response to a point designated on an imagedisplayed on the image display unit, control selecting means is providedfor selecting a control to be applied to the image photographing unitamong the plurality of controls. Accordingly, a particular control canbe designated and selected from the plurality of controls.

FIG. 11 is a block diagram showing the structure of the secondembodiment of the invention.

Referring to FIG. 11, an image communication system at the own sidestation is constituted by an image communication apparatus having aself-portrait photographing unit 117 and an image display unit 118 andother units 119 to 125. The image communication system includes variousunits shown in FIG. 12 other than the units 117 to 125, which are notdepicted in FIG. 1.

An image communication system at the partner side station is constructedin the similar manner to the system at the own side station, the unitsshown in FIG. 11 including only a communication control unit 126 fordata transfer to and from the own-side station communication system overa communication line, a partner portrait photographing unit 127 forphotographing an image at the partner side station, and a controlcompletion informing unit 128 for informing a completion of the controlof the image photographing unit at the partner side station. Image dataand a plenty of control information are transmitted and received betweenown side and partner side stations to perform, for example, a TVconference.

Referring to FIG. 11, in accordance with the notified controlinformation, the self-portrait photographing unit 117 and the partnerportrait photographing unit 127 execute a process for changing aphotographing state (photographing direction, photographing area, focalposition, and so on). The image photographing units 117 and 127 includean unrepresented controller which receives the control information andexecutes the process for changing the photographing state. When thecontrol of the photographing state is completed by using the receivedcontrol information, control completion information is supplied to aphotographing control inhibition unit 122 or a control completioninformation unit 124, depending upon which station has transmitted thecontrol information.

An image photographed by the self-portrait photographing unit 117 issupplied via a controlling time predicting unit 123 to a self-portraitdisplay window 118 a of the image display unit 118 to display the imagethereon, and is also supplied via a communication control unit 125 tothe partner side station to display the image on an unrepresented imagedisplay unit at the partner side station. An image photographed by thepartner portrait photographing unit 127 is displayed on theunrepresented image display unit at the partner side station, and alsosupplied via the communication control unit 126 to the own side stationto display the image on a partner portrait display window 118 b. Thecontrolling time predicting unit 123 measures and records frameintervals of a self-portrait image or partner portrait image sent fromthe self-portrait photographing unit 117 or communication control unit125, to calculate an average time interval of the transferred image, andalso to calculate the time required for completing the photographingstate control of the image photographing unit in accordance with thecontrol information informed by the control information informing unit120. In this manner, the controlling time predicting unit 123 predicts atime from the transmission of the photographing state controlinformation to the display of a new image on the image display unit 118after the photographing state control of the image photographing unit iscompleted in accordance with the control information.

Reference numeral 119 represents a photographing control unit displayedin the form of graphic patterns on the image display unit 118, thephotographing control unit having buttons or the like for controllingthe self-portrait photographing unit 117 or partner portraitphotographing unit 127. An operator manipulates a button of thephotographing control unit 119 with an input device such as a mouse (notshown) to control the self-portrait photographing unit 117 or partnerportrait photographing unit 127.

Control information inputted from the photographing control unit 119 isinformed to the photographing control inhibition unit 122 which in turninforms the control information to either the self-portraitphotographing unit 117 or control information informing unit 120,depending upon the contents of the control information. The controlinformation informed to the control information informing unit 120 isfurther informed via the communication control unit 125 to the partnerportrait photographing unit 127 to control the photographing statethereof. At the same time when the control information is informed, thephotographing control unit 119 informs the photographing control unit119 of a command for disabling the photographing control unit 119. Uponreception of this command, the photographing control unit 119 changesits displayed image to a disabled button image.

There are two cases where the photographing control inhibition unit 122releases the manipulation inhibition state of the photographing controlunit 119, as described in the following. In one case, the manipulationinhibition state is released when the self-portrait photographing unit117 or partner portrait photographing unit 127 receives completioninformation of the photographing state control informed via the controlcompletion information unit 128. In the other case, the manipulationinhibition state is released when a time measuring unit 121 counts up apredicated control time inquired from the control time predicting unit123. The predicted control time is a time required for a frame to bedisplayed on the image display unit 118 after the photographing statecontrol of the image photographing unit 117, 127 is completed inaccordance with the received control information. A manipulationinhibition release is informed from the photographing control inhibitionunit 22 to the photographing control unit 119 which in turn changes itsdisplayed image to a button enabled image.

In this embodiment, with the same structure shown in FIG. 2, the videointerface unit 9 and system control unit 14 realizes the operations ofthe photographing control unit 119, control information informing unit120, time measuring unit 121, photographing control inhibition unit 122,control time predicting unit 123, and control completion informing unit124, respectively shown in FIG. 11.

FIG. 12 is a sequence chart illustrating a process flow when thephotographing control inhibition unit is controlled by the control timepredicting unit and time measuring unit in the TV conference system ofthis embodiment. The process flow of this sequence chart will bedescribed with reference to the block diagram shown in FIG. 11.

Referring to FIG. 12, at Step S400 as an operator inputs photographingstate control information of the partner portrait photographing unit 127to the photographing control unit 119, the inputted information istransmitted at Step S401 to the partner side station via thephotographing control inhibition unit 122, control information notifyingunit 120, and communication control unit 125. Then, at the own sidestation, the photographing control inhibition unit 122 disables thephotographing control unit 119 at Step S402, and a predicted controltime (T1) is received from the control time predicting unit 123 at StepS403. The predicted control time is a predicted time required forcompleting the designated control, and is a time period until an imageis received after the control of the partner portrait photographing unit127 is completed. In this case, if a state display on the photographingcontrol unit 119 is a graphic representation, its graphic representationis changed to a graphic representation indicating a manipulationinhibition state. For example, the icon for a camera control shown inFIG. 11 is changed to a graphic representation indicating a manipulationinhibition state. At Step S401, the time measuring unit 121 startscounting the predicted control time to check whether the predictedcontrol time has lapsed. The manipulation inhibition state of thephotographing control unit 119 is maintained until the predicted controltime has lapsed.

At the partner side station, in accordance with the photographing statecontrol information informed at Step S401, the photographing statecontrol (e.g,.camera tilt) of the partner portrait photographing unit127 starts at Step S406 when the photographing state control informationis received. In this case, an image while the photographing state ischanged (e.g., camera is tilted) is transmitted to the own side stationas illustrated at Steps S407 and S409 to display it on the image displayunit 118 at the own side station at Steps S408 and S410. In thisexample, the photographing state control of the image photographing unit127 at the partner station is completed at Step S411. Therefore, animage transmitted at Step S412 is the first image. The time from whenthe photographing state control information is transmitted to thepartner side station at Step S401 to when the first image is transmittedto the own side station after the control completion of the partnerportrait photographing unit 127 is represented by T2.

When the count of the predicted control time T1 by the time measuringunit 121 is completed at Step S414, the photographing control inhibitionunit 122 releases the manipulation inhibition state of the photographingcontrol unit 119. If a state display on the photographing control unit119 is a graphic representation, its graphic representation is changedto the graphic representation indicating a manipulation inhibitionreleased state, such as shown in FIG. 11.

Similar to Steps S400 and S401, an input of photographing state controlinformation by an operator becomes possible at Step S416, the controlinformation is transmitted to the partner side station at Step S417, andsimilar operations are repeated.

In the above description, the predicted control time T1 is assumed to belonger than the time T2.

FIG. 13 is a sequence chart illustrating a process flow when thephotographing control inhibition unit is controlled by the controlcompletion informing unit in the TV conference system of thisembodiment. The process flow of this sequence chart will be describedwith reference to the block diagram shown in FIG. 11.

Referring to FIG. 13, at Step S500 as an operator inputs photographingstate control information of the partner portrait photographing unit 127to the photographing control unit 119, the inputted information istransmitted at Step S501 to the partner side station via thephotographing control inhibition unit 122, control information notifyingunit 120, and communication control unit 125. Then, at the own sidestation, the photographing control inhibition unit 122 disables thephotographing control unit 119 at Step S502. In this case, if a statedisplay on the photographing control unit 119 is a graphicrepresentation, its graphic representation is changed to a graphicrepresentation indicating a manipulation inhibition state.

At the partner side station, in accordance with the photographing statecontrol information informed at Step S501, the photographing statecontrol (e.g, camera tilt) of the partner portrait photographing unit127 starts at Step S503 when the photographing state control informationis received. In this case, an image while the photographing state ischanged (e.g., camera is tilted) is transmitted to the own side stationas illustrated at Steps S504 and S506 to display it on the image displayunit 118 at the own side station at Steps S505 and S507. In thisexample, the photographing state control of the image photographing unit127 at the partner station is completed at Step S508. Therefore, animage transmitted at Step S509 is the first image. The first image isdisplayed on the image display unit 118 at the own side station at StepS510.

At the partner side station, when the first image is transmitted at StepS509 after the photographing state control is completed, a photographingstate control completion is transmitted at Step S511 to the own sidestation via the control completion informing unit 128 and communicationcontrol unit 126. Upon reception of the control completion, the imagephotographing control inhibition unit 122 at the own side stationreleases at Step S511 the manipulation inhibition state of thephotographing control unit 119 set at Step S502. If a state display onthe photographing control unit 119 is a graphic representation, itsgraphic representation is changed to the graphic representationindicating a manipulation inhibition released state.

Similar to Steps S500 and S501, an input of photographing state controlinformation by an operator becomes possible at Step S513, the controlinformation is transmitted to the partner side station at Step S514, andsimilar operations are repeated.

FIG. 14 is a flow chart illustrating an operation when controlinformation is inputted from the photographing control unit while thephotographing control inhibition unit is controlled by the control timepredicting unit and time measuring unit in the TV conference system ofthis embodiment. The process of this flow chart will be described withreference to the block diagram shown in FIG. 11.

Referring to FIG. 14, at Step S600 as an operator inputs photographingstate control information of the partner portrait photographing unit 127to the photographing control unit 119, the inputted information istransmitted to the partner side station via the photographing controlinhibition unit 122, control information notifying unit 120, andcommunication control unit 125, and the flow advances to Step S601.

At Step S601, the photographing control inhibition unit 122 informed ofthe control information at Step S600 sets the manipulation inhibitionstate of the photographing control unit 119, and the flow advances toStep S602.

At Step S602, the photographing control inhibition unit 122 receives thepredicted control time from the control time predicting unit 123, thepredicted control time being a time required for the transmission of animage after the control of the partner portrait photographing unit 127is completed in accordance with the received control information. Then,the flow advances to Step S603.

At Step S603, the time measuring unit 121 starts counting up thepredicted control time received at Step S602, and the flow advances toStep S604.

At Step S604, the time count started at Step S603 is checked, and if thepredicted control time received at Step S602 has lapsed (Yes at StepS604), then the flow advances to Step S605, whereas if not (No at StepS604), the process at Step S604 is repeated.

At Step S605, the manipulation inhibition state of the photographingcontrol unit set at Step S601 is released to terminate the process flow.

FIG. 15 is a flow chart illustrating an operation when controlinformation is inputted from the photographing control unit while thephotographing control inhibition unit is controlled by the controlcompletion informing unit in the TV conference system of thisembodiment. The process of this flow chart will be described withreference to the block diagram shown in FIG. 11.

Referring to FIG. 15, at Step S700 as an operator inputs photographingstate control information of the partner portrait photographing unit 127to the photographing control unit 119, the inputted information istransmitted to the partner side station via the photographing controlinhibition unit 122, control information notifying unit 120, andcommunication control unit 125, and the flow advances to Step S701.

At Step S701, the photographing control inhibition unit 122 informed ofthe control information at Step S700 sets the manipulation inhibitionstate of the photographing control unit 119, and the flow advances toStep S702.

At Step S702, it is checked whether the photographing state control ofthe partner portrait photographing unit has been completed in accordancewith the control information informed at Step S700 and whether thepartner side station has transmitted an image after the photographingstate control completion. If the control completion has been informed(Yes at Step S702), the flow advances to Step S703, whereas if not (Noat Step S702), the process at Step S702 is repeated.

At Step S703, the manipulation inhibition state of the photographingcontrol unit set at Step S701 is released to terminate the process flow.

FIG. 16 is a flow chart illustrating an operation when controlinformation is inputted from the photographing control unit while thephotographing control inhibition unit is controlled by the controlcompletion informing unit in the TV conference system of thisembodiment. The process of this flow chart will be described withreference to the block diagram shown in FIG. 11.

Referring to FIG. 16, at Step S800 the control of the imagephotographing unit 117 starts in accordance with control informationreceived from the partner side station, and the flow advances to StepS801.

At Step S801, it is checked whether the control (e.g., camera tilt) ofthe image photographing unit 117 started at Step S800 has completed. Ifcompleted (Yes at Step S801), the flow advances to Step S802, whereas ifnot (No at Step S801), the process at Step S801 is repeated.

At Step S802, it is checked whether the image photographing unit 117 hastransmitted a new image to the partner side station via thecommunication control unit 125 after the control completion of the imagephotographing unit 117 detected at Step S801. If transmitted (Yes atStep S802), the flow advances to Step S803, whereas if not (No at StepS802), the process at Step S802 is repeated. In the structure shown inFIG. 11, it is assumed that after an image is transmitted after thecontrol completion, the image photographing unit 117 informs the controlcompletion informing unit 124 of an image transmission completion.

At Step S803, the control completion informing unit 124 informs thecommunication control unit 125 of a transmission of an image after thecontrol completion of the image photographing unit 117 in accordancewith the received control information by which the process flow isactivated. Thereafter, the process flow is terminated.

As described above, the TV conference system of this embodiment includesan image photographing unit capable of being remotely controlled bycontrol information, an image display unit for displaying an imagephotographed by the image photographing unit, a photographing controlunit for remotely controlling the image photographing unit, controlinformation informing means for informing the image photographing unitof control information inputted by the photographing control unit, atime measuring unit for counting a predetermined lapse time after thecontrol information informing means informs the control information, andphotographing control inhibition means for disabling the photographingcontrol unit until the time measuring unit counts up the predeterminedlapse time after the control information informing unit transmits thecontrol information. Accordingly, the photographing control unit can bedisabled for the predetermined time after the control information of aphotographing state is transmitted to the image photographing unit atthe partner side station. It is also possible to prevent inadvertentlydepressing an operation key of the photographing control unit andthereby facilitate the system operation, because an image is transmittedwhile the photographing state of the image photographing unit at thepartner side is changed.

Further, according to another aspect of the embodiment, the TVconference system further includes control time predicting means forpredicting a time from when the control of the image photographing unitis completed in accordance with the control information informed by thecontrol information informing unit to when a new image is transmittedafter the control completion, wherein the predetermined lapse timecounted by the time measuring unit is set longer than a control timepredicted by the control time predicting means. Accordingly, the timeperiod while the photographing control unit is disabled after thephotographing state control information is transmitted to the imagephotographing unit, can be automatically calculated. Therefore, anoperator is not required to consider the time period while thephotographing control unit is disabled, facilitating the systemoperation.

Still further, according to still another aspect of this embodiment, theTV conference system includes an image photographing unit capable ofbeing remotely controlled by control information, an image display unitfor displaying an image photographed by the image photographing unit, aphotographing control unit for remotely controlling the imagephotographing unit, control information informing means for informingthe image photographing unit of control information inputted by thephotographing control unit, control completion informing means forinforming the station received the control information of a controlcompletion after a frame is transmitted after the control completion ofthe image photographing unit by the received control information, andphotographing control prohibition means for disabling the photographingcontrol unit during the time from when the control information informingmeans informs the control information to when the control completion isreceived from the control completion informing means. Accordingly, thephotographing control unit can be disabled during the time from when thecontrol of the image photographing unit at the partner side station iscompleted in accordance with the control information of a photographingstate to when the control completion is received after an image istransmitted. It is therefore possible to prevent inadvertentlydepressing an operation key of the photographing control unit andthereby facilitate the system operation, because an image is transmittedwhile the photographing state of the image photographing unit at thepartner side is changed.

Furthermore, according to another aspect of the embodiment, thephotographing control unit is realized by a graphical user interfacedisplayed on the image display unit, and the graphic representation ofthe photographing control unit is changed depending upon whether thephotographing control inhibition means has disabled the photographingcontrol unit. Accordingly, it is possible to visually display amanipulation inhibition state of the photographing control unit, and anoperator can know easily whether the photographing control unit can beused or not.

What is claimed is:
 1. An image communication apparatus comprising: a command generator for generating a command for controlling a communication partner, to cause a part of the communication partner to move mechanically, the command being transmitted through a communication line; and a prevention unit for preventing the communication partner from operating incorrectly according to a command that is transmitted after a predetermined delay time of the communication line, wherein said prevention unit includes a designation unit for directly designating a position of an image of a whole scene displayed on a display unit, the image being transmitted from the communication partner.
 2. An image communication apparatus according to claim 1, wherein said prevention unit further includes: a generator prevention unit for preventing said command generator from generating another command at least within the predetermined delay time after said command generator generates the command.
 3. An image communication apparatus according to claim 1, further comprising: a receiver for receiving, from the communication partner, a status according to the command transmitted to the communication partner, wherein said prevention unit prevents said command generator from generating another command until said receiver receives the status.
 4. An image communication apparatus according to claim 1, wherein the communication line is a public line.
 5. An image communication apparatus according to claim 1, wherein the communication line is a wireless communication channel.
 6. An apparatus according to claim 1, wherein the communication partner includes an image pickup unit, and the part of the communication partner that is caused to move mechanically in accordance with the command is a mechanical part that changes an image pickup area of the image pickup unit.
 7. An apparatus according to claim 6, wherein the mechanical part changes the image pickup area by controlling a focal length of a lens of the image pickup unit.
 8. An image communication method, said method comprising the steps of: generating a command for controlling a communication partner, to cause a part of the communication partner to move mechanically, the command being transmitted through a communication line; and preventing the communication partner from operating incorrectly according to a command that is transmitted after a predetermined delay time of the communication line, wherein said preventing step includes the step of directly designating a position of an image of a whole scene displayed on a display unit, the image being transmitted from the communication partner.
 9. An image communication method according to claim 8, wherein said preventing step further includes: a command generation prevention step of preventing generation of another command at least within the predetermined delay time after said generating step generates the command.
 10. An image communication method according to claim 8, further comprising the step of receiving, from the communication partner, a status according to the command transmitted to the communication partner, wherein said preventing step prevents said generating step from generating another command until the status is received.
 11. An image communication method according to claim 8, wherein the communication line is a public line.
 12. An image communication method according to claim 8, wherein the communication line is a wireless communication channel.
 13. Am image communication method according to claim 8, wherein the communication partner includes an image pickup unit, and the part of the communication partner that is caused to move mechanically in accordance with the command is a mechanical part that changes an image pickup area of the image pickup unit.
 14. An image communication method according to claim 13, wherein the mechanical part changes the image pickup area by controlling a focal length of a lens of the image pickup unit. 